1. Institute of Materials for Electronics and Magnetism, IMEM-CNR, Trento Unit c/o Fondazione Bruno Kessler, Via alla Cascata 56/C, Povo, Trento IT-38123, Italy
2. Department of Microelectronics and Computer Engineering/ECTM/DIMES, Delft University of Technology, Feldmanweg 17, 2628 CT Delft, Netherlands